/*
    GNU GENERAL PUBLIC LICENSE
    Copyright (C) 2006 The Lobo Project

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public
    License as published by the Free Software Foundation; either
    verion 2 of the License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    General Public License for more details.

    You should have received a copy of the GNU General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Contact info: lobochief@users.sourceforge.net
*/
package org.lobobrowser.settings;

import java.io.Serializable;

import org.lobobrowser.store.StorageManager;
import org.lobobrowser.util.*;
import org.lobobrowser.security.*;
import org.lobobrowser.store.*;

/**
 * Browser cache settings. This is a singleton class
 * with an instance obtained by calling {@link #getInstance()}.
 */
public class CacheSettings implements Serializable {
    private static final CacheSettings instance;
    private static final long serialVersionUID = 22574500900000604L;

    static {
    	CacheSettings ins = null;
		try {
			ins = (CacheSettings) StorageManager.getInstance().retrieveSettings(CacheSettings.class.getSimpleName(), CacheSettings.class.getClassLoader());
		} catch(Exception err) {
		}
		if(ins == null) {
			ins = new CacheSettings();
		}
		instance = ins;    	
    }

    /**
     * Gets the class singleton.
     */
    public static CacheSettings getInstance() {
    	SecurityManager sm = System.getSecurityManager();
    	if(sm != null) {
    		sm.checkPermission(GenericLocalPermission.EXT_GENERIC);
    	}
    	return instance;
    }
    
    public void save() {
    	try {
    		StorageManager.getInstance().saveSettings(this.getClass().getSimpleName(), this);
    	} catch(java.io.IOException ioe) {
    	}
    }

    private CacheSettings() {
    	resetDefaults();
    }
    
    public void resetDefaults() {
    	this.setMaxRAMCacheSize(5 * 1024 * 1024);
    	this.setDefaultCacheExpirationOffset(60);
    }
    
	public int getMaxRAMCacheSize() {
		return CacheManager.getInstance().getMaxTransientCacheSize();
	}

	/**
	 * Sets the approximate maximum RAM cache size.
	 * @param maxRAMCacheSize The maximum cache size in bytes.
	 */
	public void setMaxRAMCacheSize(int maxRAMCacheSize) {
		CacheManager.getInstance().setMaxTransientCacheSize(maxRAMCacheSize);
	}
    
    private int defaultCacheExpirationOffset;

	public int getDefaultCacheExpirationOffset() {
		return defaultCacheExpirationOffset;
	}

	/**
	 * Sets the default offset in seconds added to
	 * the response cache timestamp to get the
	 * expiration time of a document. This is used
	 * with cacheable documents
	 * when max-age and the Expires header are missing.
	 */
	public void setDefaultCacheExpirationOffset(int defaultCacheExpirationOffset) {
		this.defaultCacheExpirationOffset = defaultCacheExpirationOffset;
	}
}
